The present invention pertains to a flue gas purification system with a fluidized bed reactor that features a flue gas inlet unit and a flue gas outlet unit.
Flue gas purification systems are extensively known from the prior art. A system of this type is described, for example, in WO 2006/032288 A1. Such systems are used for carrying out methods for the separation of noxious gases such as, for example, HCl, HF or SO2. Dioxins, furanes and heavy metals such as, for example, mercury can also be effectively separated if so-called sorbents such as hearth-type furnace coke, activated carbon or the like is also added. Fluidized bed reactors, into which the flue gas to be purified is introduced via a flue gas inlet unit, may be used for carrying out this method. This unit usually consists of a pipeline that arrives from the boiler and features one or more outlets into the reactor area. A sorbent is placed or introduced into the reactor. A fluidized bed is then conventionally formed. Reactors may be operated with circulating fluidized beds or entrained beds. The flue gas and the sorbent react with one another and the noxious gases are separated from the flue gas in this fashion. The entire gas, i.e., the flue gas with the entrained separation residues and sorbent residues, is transferred into a downstream separation unit that usually consists of filter units via a flue gas outlet unit. In the filter unit, the separation residues are separated from the flue gas and the flue gas is subsequently released. The separation residues are partially returned to the fluidized bed reactor or disposed of and reused.
In large systems with volumetric flue gas flows greater than 2,000,000 Nm3/h, it is necessary to operate several absorbers on the inlet side because the flow processes against and through the absorption zone, the distribution of solid matter, the temperature distribution, as well as pressure losses and, if applicable, soiling and depositing tendencies require such a parallel operation.
In large systems with, for example, volumetric flue gas flows greater than 2,000,000 Nm3/h, it is furthermore necessary to operate two or more flue gas purification systems in parallel because the capacity of the filter units arranged downstream of the reactor is limited. Such filter units consist, for example, of conventional bag filter units, electric filters or the like.
Based on the known prior art, the present invention aims to solve the problem of additionally developing a flue gas purification system of the initially cited type in such a way that the use of only one absorber also suffices in large systems.